Overexpression of PD-L1 in papillary carcinoma and its association with clinicopathological variables

Abstract

Aim: Standard treatment may not be sufficient in patients with metastatic papillary thyroid cancer (PTC), and it may be beneficial to add PD-1 agents to the treatment. Therefore, this study was conducted to compare and evaluate the expression of PD-L1 in patients with nodular goiter (NG) and Hashimoto's thyroiditis (HT) within the scope of PTC carcinoma. Material and Methods: Thirty-five patients from each group who underwent thyroidectomy for NG, HT, and PTC, between January 2011 and December 2017 were identified. Immunohistochemically, an anti-PD-L1 stain was applied by taking new sections from the tissue samples of 105 patients. The histological type, tumour diameter, capsule invasion (CI), and lymphovascular invasion (LVI) were evaluated. Results: Nine (25.7%) of the patients with PTC were defined as classic, 10 (28.6%) as follicular, 6 (17.1%) as oncocytic, 5 (14.3%) as encapsulated, 2 (5.7%) as solid, 1 (2.9%) tall cell, and 2 (5.7%) as Warthin-like. The expression of PD-L1 in the patients with PTC was significantly higher than in the patients with NG and HT (p<0.001). There was a significant relationship between the increased PD-L1 expression and staining intensity and presence of thyroid LVI in the patients with PTC (p=0.047). In addition, the PD-L1 expression and LVI were observed to be more severe in patients with follicular, tall cell, and oncocytic subtype PTC (p=0.011, p=0.026, respectively). Conclusion: It was observed that the PD-L1 expression increased in patients with PTC. PD-L1 expression and LVI were more severe in patients with follicular, tall cell, and oncocytic subtype of PTC. © 2021, Duzce University Medical School. All rights reserved.

Amaç: Metastatik papiller tiroid kanserli (papillary thyroid cancer, PTC) hastalarda standart tedavi yeterli olmayabilir ve tedaviye anti-PD-1 ajanların da eklenmesi faydalı olabilir. Bu nedenle bu çalışma, PTC karsinomu kapsamında, nodüler guatr (NG) ve Hashimoto tiroiditi (HT) hastalarında PD-L1 ekspresyonunun karşılaştırılması ve değerlendirilmesi amacıyla yapılmıştır. Gereç ve Yöntemler: Ocak 2011 ile Aralık 2017 tarihleri arasında, NG, HT ve PTC nedeniyle tiroidektomi yapılmış olan, her hasta grubundan otuz beş hasta belirlendi. 105 hastanın doku örneklerinden yeni kesitler alınarak immünohistokimyasal olarak anti-PD-L1 boyası uygulandı. Histolojik tip, tümör çapı, kapsül invazyon (capsule invasion, CI) ve lenfovasküler invazyon (lymphovascular invasion, LVI) değerlendirildi. Bulgular: PTC tanısı alan hastaların 9’u (%25,7) klasik, 10’u (%28,6) foliküler, 6’sı (%17,1) onkositik, 5’i (%14,3) enkapsüle, 2’si (%5,7) solid, 1’i (%2,9) uzun hücreli ve 2’si (%5,7) Warthin benzeri tip olarak tanımlandı. PTC’li hastalarda PD-L1 ekspresyonu, NG ve HT olan hastalardan anlamlı olarak daha yüksekti (p<0,001). PTC’li hastalarda artmış PD-L1 ekspresyonu ve boyama yoğunluğu ile tiroid LVI varlığı arasında anlamlı bir ilişki vardı (p=0.047). Ayrıca foliküler, uzun hücreli ve onkositik alt tip PTC’li hastalarda PD-L1 ekspresyonu ve LVI’nın daha şiddetli olduğu gözlendi (sırasıyla p=0,011, p=0,026). Sonuç: PTC’li hastalarda PD-L1 ekspresyonunun arttığı gözlendi. Foliküler, uzun hücreli ve onkositik alt tip PTC’li hastalarda PD-L1 ekspresyonu ve LVI’nın daha şiddetli olduğu gözlendi.